For certain character of patient care fluidized hospital beds have been in use for a considerable period of time. For example, during skin grafting procedures and for control of pressure induced lesions or bed sores and the like fluidized hospital beds have been found to provide considerable patient benefit. Beds of this character however have a number of significant drawbacks which in many cases have given hospitals, rest homes and other facilities cause for concern. For example in many cases for patient comfort and safety it is absolutely necessary that the air bag patient support devices remain inflated at all times. In the case of electrical power failure or failure of the air supply, the patient support bags of a fluidized hospital bed can collapse in a short period of time, perhaps causing significant injury to the patient or at least adversively affecting the progress of the patient towards a more healthy condition. It is desirable therefore to provide a fluidized hospital bed system which will remain inflated at all times even under circumstances of electrical utility power failure and in case of mechanical or electrical failure of the air supply system.
Another adverse feature of fluidized hospital beds is the fact that the air bags of the bed are quite soft and the fabric material of the fluidized air bags tends to "wrap around" the patient thus preventing ambient air from reaching a good portion of the patients' body. In this case there is a significant tendency for the patient to perspire heavily in areas where this wrap around effect occurs. Continuous excessive perspiration can maintain excessive moisture present at the patients skin for extended periods of time, thus adversely affecting the comfort and eventual recovery of the patient. This wrap around effect also tends to force the shoulders of the patient toward one another, developing a condition of sunken chestedness which is quite uncomfortable to the patient and causes spinal trauma. It is desirable therefore to provide a fluidized hospital bed system incorporating air bag structures which do not have a patient wrap around effect and thus prevent excessive moisture buildup from perspiration and also prevent sunken chestedness of the patient. Additionally, it is desirable to provide for air flow immediatly beneath the patient to remove moisture and to provide for patient heating and cooling as desired for optimum patient care.
Another drawback of conventional fluidized hospital bed systems arises in the event of emergency conditions, such as cardiac arrest for example. In the event of cardiac arrest it is frequently necessary for nursing personnel to conduct cardiac pulmonary resuscitation (CPR) activities. These activities cannot be conducted effeciently on soft platforms as are typically provided by fluidized hospital bed systems. In this case, the patient must sometimes be moved rapidly to the floor or to a stable platform to enable CPR activities to be conducted. The additional trauma caused by rapid patient transfer is detrimental to the safety and health of the patient. Presently available fluidized bed systems are quite slow to render to a stable platform condition. In one such system the blower must be deenergized and the air supply hose removed from the air supply mainfold before the air bags can be rapidly deflated. It is desirable therefore to provide a fluidized hospital bed system which can be selectively controlled by nursing personnel to rapidly deflate the air bags and provide a stable platform for the patient without necessitating removal of the patient from the hospital bed and thereby minimizing trauma to the patient.